Power actuator



Oct. 6, 1931. c. s. BRAGG ET AL POWER ACTUATOR Original Filed Jan. 5,1925 ATTORNEY Patented Oct. 6, 1931 UNTTED sTATEs PATENT oEFlcE CALEB S.BRAGG ANDVVICTOR W. KLIESRATH, F LONG ISLAND CITY, NEW YORK, AS- SIGNOBSCIJO BBAGG-KLIESRATH CORPORATION, 0F LONG ISLAND CITY, NEW' YORK,

A CORPORATION 0F NEW YORK POWER ACTUATOB vOriginal application filedJanuary 5, 19'2, Serial No. 506. Divided and this application tiledAugust 80,

192s. serial No. 132,367. Renewed December 1o, 1980.

. Our invention consists in the novel features hereinafter described,reference being had to the accompanying drawings, which illustrate oneembodiment ofv the same, se-

@ lected by us for purposes of illustration, and the. said invention isvfully disclosed in the following description and claims.

This application is a division'of. our former application filed January5,1925, and given l0 Serial No. 506. l

-Our invention relates to a power actuator,

adapt-ed especiall for use in connection with -tautomotive vehic espropelled by an internal 'combustion engine, and most convenientlyoperated by suctionl from a suction passage of the engine between thethrottle valve and the engine cylinder, or cylinders, as for example, bymeans of a connection with the intake manifold of the engine. In ourprior app'li.

0 cation for Letters Patent of the United States filed December 22,1923, Serial No. 682,346,

we' have disclosed apower actuator of this general type connected withthe intake manifold of the internal combustion engine by means of a pipeor passage in which are located an adjustable regulatin valve or otherrestricting means, a check valve, and a storage space, or tank, andcomprising a cylinder, a double acting piston therein, and reversingvalve mechanism for' applying differential pressures on, opposite facesof the piston, and said actuator being combined with a' fot lever, orother part to be actuated in suchv manner that the latter can beoperated by the actuator under the control of the foot'lever while theoperator may add his physical power to the power of the actuator whendesired,

s or in case of failure of the actuator, may

positively operate the actuated part by physical power applied to thefoot lever, or other operator operated part.

The regulating valve or other restricting device prevents such largevolumes of air being drawn into the intake manifold as to betherethrough, so as to stall the engine when idling while the storagespace or storage tank provides a large space in which a partial vacuumor Tarification is maintained at all times.

4outer side of the piston being connected with Vtheatmosphere, and theimmediate result is li kelyto dilute the explosive charges passingywhile the engine is running, by withdrawingA tank, in the suction lineextending to the in take manifold exterior to the actuator cylinder, andmaintain a condition of partial vacuum or rariiication within theactuator cylinder itself, on both sides of the piston, which is made tosupply the necessary storage space.

Thereby w'e obtain a number of important and advantageous results in theconstruction, installation andoperation of the power' actuator. In thefirst place, the tank, which is a bulky element, is entirely done awaywith and the construction is correspondingly simplified and' renderedless expensive. As a partial vacuum is maintained within the actuatorcylinder on both sides of the piston therein,

when the device is in normal or inoperative osition, when the reversingvalve mechanism 1s moved into a position to effect the operation of theactuator, one end of the cylinder on one side of-'the piston isconnected with the intake manifoldor other vacuum roducing means, theother end of the cylin er on the that the atmospheric air rushes intothe end of the c linder to which it is admitted, and effects t eoperation of the iston in the desired direction and to the desiredextent with,-l

out any appreciable quantity of air being actually withdrawn from thecylinder and vadmitted to the intakefmanifold or other sucton isv movedin the opposite direction.

the brake'is applied the actuator is operated without any materialadmission of air tothe intake manifold, and therefore without anypossibility of injuriousl affecting the explosive mixture or of stal ingthe engine, and

e when the valve mechanism is reversed to ef- 90 can be graduallyWithdrawn to the intake feet the release of the brakes, by operating thepiston in the opposite direction, the atmospheric air admitted for thepurpose of obtaining the previous application ofthe brakes manifold,under the control of the regulating valve, so'as to prevent interferencewith the o eration of the engine, while securing the eective release ofthe brake mechanism. If the motor should stall, due to the admission ofthis air when the brakes are being released, it would be a matter'offar'less importance than the stalling of the motor when the brakes arebeing applied. It is not so important that the movement of the iston ina direction to release the brakes' s all be as rapid as the movement ofthe piston in the direction to ap ly the brakes. As a matter of fact, avery s ight movement of the piston in the directlon to release thebrakes would be suiiicient to release them, and for this reasoncontinuedap lication'and releasing of the brakes without a lowing theiston to come to the at rest position may effected with comparativelysm-all amount of air being drawn into the intake manifold, and thepiston may be permitted to return to its normal position after anapplication of the brakes more slowly than it wouldbedesirable to haveit moved in the opposite direction. Furthermore, when the piston comesto the at rest positlon after an application of the brakes,

artial vacuum in the rear of the erefore; the -only, air to he exthereis a cylinder.

-hausted is the amount admitted to the forward end of the cylinder toeect the releasing of the brakes, which is considerably less than thetotal amount of air that could be contained in the cylinder, were it notfor our invention, which continuallykeeps at least one-end of ourcylinder under vacuum, the total amount'of air inl the cylinder would.have to be exhausted after each operation of the brakes. Y

Our invention therefore enables us to simplify and decrease the costofthe apparatus, and at the same time insures the most eicient operationof the actuator without prejudice to the continuous andeicient'operation of the internal combustion engine .cally to anot fromthe suction passage of which the necessary power or suction for theoperation of the actuator is derived.

In our former application above referred to, these features are broadlyclaimed, together with one of the specific embodiments or carrying ourinvention into effect, and

the presentapplication is directed specifier specifieembodiment forcarrying the inventlon into eiect disclosed in our 'previous applicationabove referred to, but not specifica l claimed therein, but which isspecifically c aimed in this application.

Referring to the accompanying drawings Fig. 1 represents a diagrammaticview of an installatronin which ourfimproved ower actuator is connectedwith themterna combustion engine of an automotive vehicle for theoperation of lthe brake mechanismTthere-` Fig. 2 is an enlargedsectional view i1- lustrating one form of'our improved actuator havingone embodiment of our present invention therein, a portion ofthe pistonrod' and-'valve actuating sleeve being Ibroken away and showing thepiston in normal retracted position.

Fig. 3 is a detail sectional view of the termmaLportions ofthe pistonrod and valve" actuating sleeve omitted from Fig. 2.

Fig. 4 is a detail sectional view of a portion of the construction shownin Fig. 2.

In Fig. 1 of the accompanying drawin we have shown diagrammatically aninstali]- tion suitable for use in-an automotive vehicle in which one ofour improved actuators is shown as interposed in the connections betweena foot lever, 88, and brake mechanism for the vehicle, diaI ammatica lyrepresented at 70, 71 and 2, indicating a brake drum, brake band andbrake lever. It will be understood that the brake mechanism will beprovided with the usual retracting means for restoring it and assistingin restoring the piston of the actuator to the retracted or normalposition, said means being indicated diagrammatically in Fig. 1, by thespring, 74. 60 represents an internal combustion enginefor propellingthe'vehicle, and provided with an intake manifold, indicated at 61, andcommunicating with the carburetor, 6l, to which is connected a ipe, 62between the throttle valve, indicate at 61", and the engine cylinders,in which pi are located preferably an adjustable regu atingvalve, orrestricting valve, 64, check valve 65, 'and a vent valve, 67 normallyclosed, and openin outwardly. The pipe, 62, communicates witg one of ourim roved power actuators, the cylinder of which is indica-ted at 701, inFig..1, the saidl nected to a link, 85, with the foot lever, 88, whichis provided with the usual retracting spring, 89, and the piston rod,205, of the actuator is connected by a link, 7 3,- with the brake lever,72.

ln Fig. 2 we have shown one form of our improved actuator embodying ourpresent invention. In this figure, 701, represents the actuator cylinderclosed at both ends by heads, 702, connected by bolts, indicated at 702,in Fig. 1, or otherwise. 703 represents the double acting pistonprovided with oppositely disposed gaskets, 704. 705 represents a -hollowpiston rod which extends through a stufiing box, 706, in one end of thecylinder, and is connected at its inner end with the piston, 703. Thehub, 710, of the piston is rovided with two valve chambers, 11 and 12respectively, each of which is provided with two 4valve seats preferablyconical and coaxial with the axis of the piston. The valve chamber, 711,is provided with seats, 713 and 714, and the valve chamher, 712, isprovided with valve seats, 715 and 716. The piston hub is provided withan outlet chamber, or suction chamber, indicated at 717, whichcommunicates with each of the valve chambers through the valve seats,714 and 715. Arl'he piston hub is also provided with a higher pressurechamber, 718, in this instance communicating with the atmosphere andwith the valve seat, 716, and by a lateral passage, 719, with the valveseat, 713. The

Iii?

'valve actuating part, in this instance, the sleeve, 720, passes througha stufiing box, 721, in the cylinder head at the opposlte end of 'thecylinder from the stufiin box, 706, the

,said sleeve extending lon itu inall through the piston hub and va vecham ers, and through the hollow piston rod, 705, and beingiongitudinally movable to eiiect the operation of the reversing valves.The valve sleeve may. be made conveniently in two parts, 720 and 720, ifdesired, and as herein shown, is provided with a pair of oppositelydisposed poppet valves in each valve cham- 'fer, the said valves beingpreferably ormed of molded rubber and frictionally engaging 'the sleeve,so that the sleeve may move through the valve while forming an air-tightjoint therewith. The valves are indicated at 740, 741, 742 and 743, thevalves, 741 and 742 hein suction valves, and the valves, 744) and 743eing air inlet valves. The valves are -1 yieldingly held in engagementwith their seats, preferably by an elastic cushioning device interposedbetween the palrs-.of valves, and indicated at 750. The actuatlng sleeveis provided with suitable means for opening one valve of'each pair whenthe sleeve is moved in either direction. 1n this instance sleeve isshown provided with a fixed collar, 722, located adjacent to the suctionvalve, 741, and a collar, 722g, which is movable longitudinally of thesleeve, 720, by

lmeans of connecting red, 744, extendin through the hollow sleeve, 7 20,and connecte at its forward end to an actuating part adapted to be brouht into operation when the parts have reac ed their normal or retractedpositions as illustrated in Fig. 2. The valve sleeve is also providedwith collars, 731 and 732, for operating the .air inlet valves.

Communication between the suction pipe, 62, and the suction chamber,717, is effected in this instance through the hollow valve sleeve, whichis provided with a fitting, 726, at its outer end, to which the pipe,62, is connected. The fixed collar 722, is so located with respect to astop carried by the sleeve, 7 20, in this instance provided by theengagement between the inner end of the fitting or collar, 726, and theadjustable collar, 721, of the adjacent stufiing box, that when thepiston returns to its normal or retracted position, as shown in Fig. 2,the sleeve will e arrested in such osition that the fixed collar, 722,will slig tly unseat the valve, 741, permitting communication betweenthe vacuum chamber, 717, of the cylinder on the forward side of thepiston through the port or passa e,'734. The movable collar, 722, iscapab e of being moved longitudinally with respect to the valveactuating sleeve by meansof a connecting rod, 744, extending through thehollow sleeve, 720, connected to the collar, 722l at its inner end, andconnected at its forward or outer end to an actuating part, adapted tobe brought into operation when the parts have reached their normal orretracted position. In this instance we have shown the vacuum pipe, 62,connected to the sleeve by a fitting, indicated at 7,45, having a ballterminal, 746, secured in a spherical socket in the stop collar, 726, ofthe valve actuating sleeve, so as to permit the fitting, 745, to have aslightly rocking movement longitudinally of the sleeve, 720. On thisfitting, 745,'is located an adjustable collar, 747, which ma be in theform of a nut engaging a threa ed portion on the exterior of thefitting, 745, and provided with a stop pin, 748, which engages a part ofthecylinder, in this instance the valve, 7 21, of t e stufiing box, 721,`so as to rock the fitting, 745, in the direction of the arrow, Fig.2, when the valve sleevel is restored to its` retracted or normalposition, b the retracting spring of the foot pedal. n this instance theforward end of the connecting rod, 744, is screwed into the ball, 746,in such manner that the rocking movement imparted to the fitting, 745,will move the collar section, 722, in a direction toward the valve, 742far enough to slightly unseat the valve, and thus establishcommunication between the vacuum chamber, 717, and that portion of thecylinder in rear of the piston. When the valve actuating sleeve is movedforward' to actuate the brake mechanism, the opening ofthe valve, 73,-will effect a compression of the cushioning device, 750, and close thevalve, 742, restoring the movable collar section, 7 22, and connectedparts, as the projection, 7 48 is released.

The specific details of the poppet valve mechanism herein shown anddescribed form no part of our present invention, as the same isdisclosed and claimed in our former application for Letters Patent ofthe United cylin `742, effecting Van equalization'of States, filedNovember 22, 1924, and given Serial No. 751,481.

lt follows from this construction thatas soon as the engine is started,the suction produced in the-intake manifold will exhaust the air fromthe cylinder of the actuator on both sides of the piston, and maintainthe piston submerged in vacuum when retracted. If it is desired to applythe brakes, the foot lever is actuated to move the sleeve, 720., in

the direction of the arrow, Fig. 2, permitting the suction valve, 742,to close, and further opening the suction valve, 741, and opening theair inlet valve, 7 43.V This continues the action of the cylinderforward of the piston with the suction chamber, 717, and -admitsatmospheric air in rear of the piston, moving the piston forward in adirection to yapply the brakes, but no appreciable amount of air will be`drawn into the intake manifold throu h' the pipe, 62, as that portionof the (ger is already exhausted. The forward movement of the pistonwill follow any extent of 4the forward movement of the brake lever, 88,and when the brake lever stops, the piston will continue to move forwarduntil the air inlet valve, 743 closes, `so as to hold the piston andbrakes. Where 4continued applications of the brakes are desired, aslight release ofthe foot lever will open the suction valve, 742,producing 'a partialor entire equalization of pressures on o positesides of the piston, which will permit the brakes to relieve themselvesand sli htly retract 'the-A piston under the action o the retractingmeans for the brake mechanism indicated at 74 in Fig. 1. A slightforward movement of the pedal lever `will again close the suction valve,742, and open the valve, 743, admitting air in rear of the piston/andanumber of successive applications of the brakes can be made withoutadmitting material quantities of air into the intake manifold. When the'foot is removed from the foot'lever, 88, the lever will be movedrearwardly by its retracting spring, opening the suction valve, ressureswithin the cylinder on both'sides o the piston and permitting the brakesto relieve themselves, and the" further reversemovement of the sleeve, 720, will close the 'suction valve, 741, and open the air inlet valve,740, admitting atmospheric air to the cylinder forward of'the pistonthrough the opening,

733, controlled by said valve, thus returning the piston to normalposition. The piston will be arrested by engagement of its hub with theend of the cylinder. The valve yactuating sleeve will be arrested by theengagement of the collar, 726with the valve, 721, this opening thesuction valve, 741, closing the air inlet valve, 740, and holding thesuction valve, 7 41, in open position. At the same time the engagementof\the pin, 7 48, with the follower or other stationary part of the Ycylinder, will effect the opening of the suction valve, 742. When, asbefore stated, the parts come to rest, the suction chamber, 717, will,therefore, be in communication with the cyl inder on both sides of thepiston and will vexhaust the air previously admitted to effeet thereverse movement of the piston, leaving it again submerged in vacuum.The exhaustion of air from the cylinder therefore only takes placeduringand after the return stroke of the piston, and this air isdelivered graduallyto the intake manifoldby the restricting valve,64,*so that the operation of the engine will not be interfered with, andthe eduction of the air 'may be retarded as much as desired, as thefirrt movement of the piston rearwardly will relieve the pressure of thebrakes,I and it is not important that the piston should move rearwardlyas quickly as it moves 'forwardly to apply the brakes.

The withdrawal of the air may, therefore, be distributed over a greator,less period of time, according to the adjustment of the valve, 64, soas to avoid the undue dilution of the explosive charges or the feedingof too small an amount of hydrocarbon fuel, and the piston is leftsubmerged in vacuum and readyl for immediate and effective operation toapply the brakes at any moment. As the degree of suction in the suctionpassages of the engine varies from time to time, we interpose the checkvalve, 65, in the pipe, 62,-so that after the cylinder is subjected tothe greatest amount of suction, the condition of rarifcation so producedwill remain, and as the brakes are usuall operated at intervals, thegreatest possi le rariication will ordinarily exist in the cylinder ofthe actuator at all times, ready to effectively a ply the brakes in themanner before descri ed. We prefer to connect the valve actuatingsleeve, 720, 720, with the piston by `means providing for a limitedamount of lost inetion, sufficient to permit the operation of thevalves, so that after this lost motion is taken up, the physical powerof the operate.1 can be directly applied to the piston and the brakemechanism connected therewith, tov en able the ofperator to addhis'physical force i to that o the actuator,or tooperate the brakes byhis physical force alone if the power should fail for any reason, thelost motion. permitting 'the 4movement'. of the valves in any case, andserving when power lll@ fails to vent the cylinder. In. the presentinstance, as shown in Fig. 3, the section, 720, of the valve sleeve isprovided with a recessed portion, 720", and a collar, 720C, and a pistonrod, 705, is in this instance provided ywith set screws, 705, extendinginto said recess (or recesses) 720", so that when the sleeve is movedforward bylthe foot lever to apply the brakes, and the piston hasfollowed applying the brakes to the full capacit o the actuator, the oyerator may, by pu 'ing the foot lever, 88, urther` forward until therear edge of'the rece, 720", will appl his physical force to the pistonand there y to the brake mechanism, in addition to the power of theactuator. It also follows from this construction that, should the powerof the actuator fail for any reason, the operator may a ply his physicalforce to the iston and bra e mechanism to apply the bra es, the firstforward movement o the valve actuating sleeve, to take up the lostmotion, movin the valves into position to vent the cylinder forward ofthe piston and admit air in rear of the piston to permit this movement.In like manner, when the foot lever V is released, the retracting springwill move it rearwardly and shift-the valve actuati sleeve so as to ventthe cylinder y(in case o failure of power) and the forward end of therecel-SS,A 720D. v

It ,will be noted that a vacuum is continuously' maintained in theactuator cylinder on both sides of the piston when it is in nor- Inalposition, so that the cylinder itself acts as a storage space and noadditional tank or other extra'- neous stora e space is required. As wehave termed it, t e piston is normally maintained Submergedin vacuum. y

What we claim-and desire to secure by Letters Patent is v 1. In a poweractuator, the combination of a cylinder closed at both ends, a doubleacting piston in said cylinder, reversing valve mechanism, means forconnecting saldi-'eversing valve mechanism with' sources of high and lowfluid pressure, a longtudinall movable valve operating partprovided witvalve engaging devices fixed in relation thereto, for

operating certainof said-valves, an o rator operated part connected withsaid va v e o erating part, a retractin spring operative y connectedwithv said va' ve operating part, means for arresting said valve orating part when the piston is in retracte position, in position to holdone of said valves o n to connect the cylinder on one side of t e pis-vton with the low pressure source, means carried o 'n said valveactuating part and, Inovable independently with respect to said valveactuating' part for operatively engaging another of said valves, andmeans for arresting said independently movable valve engaging means partwhen the piston is 1n normal reacting movable part carried by andtheengine is in operation,

tracted osition to eect the opening of said other va ve and place thecylinder on the opposite side of the piston in connection with the lowpressure source. v I

2. In a ower actuator, the combination of a cylin er closed at bothends, a double piston in said cylinder, reversin valve mechanism, meansfor connectin said reversing valve mechanism with a so ce of suction andwith the atmosphere, a longitudinally extending valve actuatin partmovable with the pistonl and exten mg through apertures in said valves,and rovlded with means for opening a suction va ve, and an air inletvalve when moved in either direction including a fixed collar attachedto said valve actuating part fo'r engagin one of the suction valves, anda movable co lar on said valve actuati part and movable with respectthereto or engaging the other suction valve, means for arresting saidsleeve in position tohold one of said suction valves open when thepiston is in normal retracted position, a

said va'lve actuatin part and movable with respect thereto, andoperatively connected with said movable collar, a retracting springoperatively connected with said valve actuating part, and means foreffecting a relative movement of said movable part with respect to thevalve actuating part when the piston is in retracted position to openthe other of said suction valves, and maintain the piston vsubmerged .invacuum when retracted.

3. In va power actuator, the combination of a" cylinder closed at bothends, a double acting piston in said cylinder, reversing valve mechanismlocated in the hub of the piston, and comprising suction and inletvalves, means for connecting the suction valves with a source ofsuction, means for connectin the air inlet valves with the atmosphere,ylelding means for normallyseatin said suction and inlet valves, alongitudina ly extending valve actuating sleeve through apertures insaid parts and provided with means for opening -a suction -valve and anair inlet valve' when moved in either direction, said means including afixed collar attached to said valve actuating part adjacent to onesuction valve and a movable collar carried by said valve actuating partand movable longitudinally thereon and located adjacent to the othersuctionvalve,l means for arresting said sleeve in position to hold thesuction valve adjacent to said'A stationary collar in partially openposition, a" movable part carried by said sleeve, and movable relativelywith respect thereto, a connection from said movable part extendinglongitudinally-'of said sleeve to said movable collar, a `retractingring operatively connected with saidy va ve l actuating part, and meansfor effecting a relative movement of said movable part and said movablecollar with respect to the sleeve for positively opening the othersuction valve when the piston is in normal retracted position, tomaintain the piston submerged in vacuum when retracted.

4. In' a power actuator, the combination of a cylinder closed at bothends, a double acting piston in said cylinder, reversing valve mechanismlocated in the hub of the piston, and comprising suction and inletvalves, means for connecting the suction valves with a source ofsuction, means for connecting the air inlet valves with the atmosphere,a longitudinally extending valve -actuating sleeve through apertures insaid parts and provided With means for opening a suction valve and anair inlet valve when moved in either direction, said means including afixed collar attached to said valve actuating part adjacent to onesuction valve and a movable collar carried by said valve actuating partand movable longitudinally thereon, and located adjacent to the other.suction valve, means for arresting said sleeve in position to hold thesuction valve adjacent to said stationary collar in artially openposition, a movable part carrie by said sleeve, projecting laterallythenefrom and movable relatively with respect to the sleeve, aconnection between said movable part and said movable collar extendinglongitudinally through said sleeve a retracting spring operativelyconnected with the valve actuating part and means for effecting amovement of said movable part and said movable collar with respect tosaid sleeve, when the piston is in normal retracted position forpositively opening the other of said Suction valves, to maintain thepiston submerged in vacuum when retracted.

5. In apower actuator, the combination of a cylinder closed at bothends, a double acting piston in said cylinder. reversing valve mechanismlocated in the hub of the piston, and comprising two pairs of oppositelydisposed coaxial valves, each pair including a suction valve and an airinlet valve ,yielding means interposed between the valve of each pairfor seating the same, means for connectmg the suction valves with asource of suction, means for connecting the air inlet valves with theatmosphere, a valve actuating part extending longitudinally through oneend of the cylinder through said valves and provided with means foropening a suction valve and an airA inlet valve when moved in eitherdirection, including a fixed collar at.

tached to said valve actuating part adjacent to one suction valve and amovable collar carried by said valve actuating part, and movablelongitudinally thereon, and located adjacent to 'the other suctionvalve, an operator operated part connected with said valve actuatingpart, a retracting spring operatively connected with said valveactuating part, a stop'carried by the valve actuating part for engaginga part connected with the cylinder, when the piston is in normalretracted position, to enable said xed collar to hold its adjacentsuction valve in open position, a movable part carried by said valve'actuating part and movable with respect therel" to, connections betweensaid movable part and said movable collar, said movable part beingprovided with a portion adapted to engage a part connected with thecylinder' when the piston is in retracted position for with the cylinder'on both sides of the piston,

valves for controlling said suction and air inlet passages, and yieldingmeans normally tending to seat all of said valves, vacuum producingmeans connected with said vacuum chamber, a longitudinally extendingvalve actuating sleeve, extending through apertures in said valves andprovided with means for opening one of the suction valves and one of theair inlet valves, when moved in either direction including a collarsection fixed to said sleeve, and a movable collar section locatedbetween said suction valves, a

' retracting spring operatively connected with said valve actuatingpart, a movable part on said sleeve adapted to engagea part connectedwith the cylinder for arresting said sleeve in position to cause thestationary lcollar section to hold its adjacent suction valve partiallyopened, and a connection between said movable part and said movablecollar section for positively opening the other. of said suction valveswhen the parts are in retracted or normal position, to maintain thepiston submerged in vacuum. V

7 In an automotive vehicle provided with an internal combustion enginehaving a suction passage, the combination with power actuator comprisingamong its members a cylinder closed at both ends, a piston in saidcylinder, reversing valve mechanism in the piston, including a suctionchamber. passages connecting it with the cylinder on both sides of thepiston, air linlet passages connected with the cylinder on both sidesvof the piston, suction and air inlet valves controlling said passages,and yielding means normally tending to seat said valves, of means forconnecting the said sucton chamber with the suction passage of theengine, a valve actuating part provided with means for opening saidvalves ICO the longitudinal movement of the valve actuating part, sodisposed as to effect the opening o't' one inlet valve and one suctionvalve when the valve actuating part is moved in either direction withrespect to the piston, 'the .valve opening means for said suction valvesbeing movable with respect to each other, a. retracting springoperatively connected with said valve actuating part, means called intoaction when the piston is in normal retracted yposition to arrest thevalve actuating part,and shift said suction valve opening means withrespect to each other to maintain both suction valves in open position,and maintain the piston submerged in vacuum, an operator operated partconnected with the valve actuating part, and means for I connecting thepiston with a part to be actuated.

8. In an automotive vehicle provided with-l an internal combustionengine having a suction passage and brake mechanism for the vehicle, thecombination with a power actuator comprising among its members acylinder closed at each end, a piston in said cylinder, reversing valvemechanism located in the piston, including a suction chamber, passagesconnecting,r itwith the cylinder on both sides of theppiston, air inlet'passages connected with the cylinders on both sides of the piston,suction and air inlet valves controliing said passages, and yieldingmeans normally tending to sea-t said valves, of means for connecting the.said suction chamber with the suction passage of the engine, a valveliftnating part extending through said valvesy and to the exterior ofthe cylinder, and provided with means for opening one of said suctionvalves and one of said inlet valves when moved in either direction,including. a tixed part on said valve actuating part for engaging onesuction valve, anda part movable with respect to the valve actuatingpartand carried thereby forV engaging the other suction-valve, means forarresting the valve actuating part in position to hold one suc-- tionvalve open by said fixed openingmeans when the piston is in retractedposition, a retracting spring operatively connected with the valveactuating part, andV means for 'shifting said movable opening means to.effect the opening of the other suction valve when 'the plston 1s 1nnormal retracted posltion, to

connect the portions' of the cylinder on both sides of the piston witheach o'ther and with the suction passage of the engine, and maintain thepiston submerged in vacuum when in retracted position, .an operatoroperated part connected with said valve actuating part, and means forconnecting the piston with the brake mechanism.

9. In an automotive vehicle provided with an internal combustion enginehaving a suotion passage and brake mechanism for the vehicle, thecombination with a power actunormally tending to seat said valves, ofmeans for connecting the said suction chamber with the suction passageof the engine, a valve actuating part extending through said valves andto the exterior of the cylinder, and provided with means for opening oneof said suctionv valves and one of said inlet valves when moved ineither direction, including a fixed part on said valve actuating partfor engaging one suction valve, and a part movable with respect to thevalve actuating part and carried thereby for engaging the other suctionvalve, a@ retracting spring operatively connected with the valveactuating part, means for arresting'the valve actuating part in positionto hold one suction valve open by said fixed opening means when thepiston is in normal retracted position, lto connect the portions of thecylinder'on both sides of the pistowith each other and with the suctionpassa e of the engine, and maintain the piston sumerged in vacuumwhenpin retracted position, an o erator operated partconnected .withsaid valve actuating part, means for connecting the piston with thebrake mechanism, and neans including a provision for lost motion forconnecting the valve actuating part with the piston.

10. In an automotive vehicle rovided with an internal combustion engineaving a suc'- tion passage and brake mechanism for thc vehicle,the-combination with a power actuator comprising among its members acylinder closed at each end, a piston in said cylinder, reversinA valvemechanism located in the piston, inclu ing a suction chamber, passagesconnecting it with the cylinder on both sides of the piston. air inletpassages connected with the cylinders on both sides of the piston,

suction and air inlet valves controlling said passages, and yieldingmeans normally tending to seat said valves. of means for connecting thesaid suction chamber with the suction passage of the engine, a valveactuating part extending through said' valves and to the exterior'o'fthe cylinder, and provided with means for opening said valves includingcollars fix'ed thereto for engaging one suction valvev and the inletvalves, and a. collar movable with respect -to the valve actuating partfor opening the other suction valve, means for arresting said valveactuating part, in position to hold one of said suction valves in openposition by a fixed collar, when the piston is in retracted position, aretracting spring operatively connected with the valve actuating part, amovable device connected withl the valve actuating part for engaging apart connected with the cylinders when the piston is in normal retractedposition, and a connection from said movable part to the said movablecollar for opening the other suction valve when' the piston is inretracted osition, to connectA the portions of the cyllnder on bothsides of the piston witheach other and with the suction passage of theengine, and maintain the piston submerged `in vacuum when in retractedposition, an operator operated part connected with said valve actuatingpart, and means for connecting the piston with the' brake mechanism. i v

11. In a power actuator, a c linder, a piston movable thereinconnecte toa part to be actuated, valve mechanism for controlling differentials ofpressure to opposite sides of said piston including a valve operatingmember and valves movable with and wlth respect to said member, anelement carried by said valve operating member, means for limiting themovement of said member to hold one of the low pressure valves in openposition when the piston is in normal retracted position, and a secondelement shiftable with respect to the first element, together with meansfor shifting saidsecond Velement to open the other low pressure valveand there.

byi connect both sides of the piston with lo pressure.

12. In a power actuator, a cylinder, a piston movable therein connectedto a part to be actuated, valve mechanism for controlling dilerentialsof pressure' to opposite sides of ysaid piston including a valveoperating member and valves movable with and with respect to saidmember, an element connected to move with said valve operatlng member,vmeans to limit the movement of said valve operating member so as tohold'one of" the low pressure valves open when the piston is in normalretracted'position, and a second element movable on the valve operatingmember and engaging with the-other low renssure valve to openthe samewhen the plston is retracted, together with means for operycc ating saidsecond member.

'13. In a power actuator, a cylinder, a piston movable therein connectedwith a part to be actuated, valve mechanism for 'controllingdifferentials of pressureto opposite sides-of said piston including avalve operating meniber, and high and low pressure valves movable withand with'v respect to'said member, valve engaging elements on saidmember, means for arresting said valve operating member to hold one -ofsaid low pressure valves in open position iwhen the piston is in n ormalretracted position, and means for relatively separat-ingsaid elements toopen the other low pressure valve when the plston is retracted.

. 14. In a por. er actuator, a cylinder, a pis-- :hanane tiveseparationv of thelow pressure valves to open the same and connect thecylinder on both sides of the'piston with the source of low pressure.

15. In a power actuator, a cylinder, a pis-` ton movable therein, inletand outlet passages for conveying motive fluid to and from said cylinderto actuate said piston, valves for said passages, actuating collars forsaid valves, means for arresting one of said collars `in posltion tohold one of the .outletvalves in open position when the piston is innormal retracted position, and means Aadapted to move said actuatingcollars relatively to each other to unseat the other of said outletvalves when the piston is in retracted position, to

connect both ends of said cylinder with said outlet passage.

. In testimony whereof we tures.

CALEB S. BRAGG. VICTOR W. KIJESRATH.

ailix our signa-

